1 files changed, 531 insertions, 0 deletions
diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
new file mode 100644
index 000000000..b493de962
--- /dev/null
+++ b/drivers/misc/cxl/api.c
@@ -0,0 +1,531 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2014 IBM Corp.
+ */
+
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <misc/cxl.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/pseudo_fs.h>
+#include <linux/sched/mm.h>
+#include <linux/mmu_context.h>
+
+#include "cxl.h"
+
+/*
+ * Since we want to track memory mappings to be able to force-unmap
+ * when the AFU is no longer reachable, we need an inode. For devices
+ * opened through the cxl user API, this is not a problem, but a
+ * userland process can also get a cxl fd through the cxl_get_fd()
+ * API, which is used by the cxlflash driver.
+ *
+ * Therefore we implement our own simple pseudo-filesystem and inode
+ * allocator. We don't use the anonymous inode, as we need the
+ * meta-data associated with it (address_space) and it is shared by
+ * other drivers/processes, so it could lead to cxl unmapping VMAs
+ * from random processes.
+ */
+
+#define CXL_PSEUDO_FS_MAGIC	0x1697697f
+
+static int cxl_fs_cnt;
+static struct vfsmount *cxl_vfs_mount;
+
+static int cxl_fs_init_fs_context(struct fs_context *fc)
+{
+	return init_pseudo(fc, CXL_PSEUDO_FS_MAGIC) ? 0 : -ENOMEM;
+}
+
+static struct file_system_type cxl_fs_type = {
+	.name		= "cxl",
+	.owner		= THIS_MODULE,
+	.init_fs_context = cxl_fs_init_fs_context,
+	.kill_sb	= kill_anon_super,
+};
+
+
+void cxl_release_mapping(struct cxl_context *ctx)
+{
+	if (ctx->kernelapi && ctx->mapping)
+		simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
+}
+
+static struct file *cxl_getfile(const char *name,
+				const struct file_operations *fops,
+				void *priv, int flags)
+{
+	struct file *file;
+	struct inode *inode;
+	int rc;
+
+	/* strongly inspired by anon_inode_getfile() */
+
+	if (fops->owner && !try_module_get(fops->owner))
+		return ERR_PTR(-ENOENT);
+
+	rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
+	if (rc < 0) {
+		pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
+		file = ERR_PTR(rc);
+		goto err_module;
+	}
+
+	inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
+	if (IS_ERR(inode)) {
+		file = ERR_CAST(inode);
+		goto err_fs;
+	}
+
+	file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
+				 flags & (O_ACCMODE | O_NONBLOCK), fops);
+	if (IS_ERR(file))
+		goto err_inode;
+
+	file->private_data = priv;
+
+	return file;
+
+err_inode:
+	iput(inode);
+err_fs:
+	simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
+err_module:
+	module_put(fops->owner);
+	return file;
+}
+
+struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
+{
+	struct cxl_afu *afu;
+	struct cxl_context  *ctx;
+	int rc;
+
+	afu = cxl_pci_to_afu(dev);
+	if (IS_ERR(afu))
+		return ERR_CAST(afu);
+
+	ctx = cxl_context_alloc();
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	ctx->kernelapi = true;
+
+	/* Make it a slave context.  We can promote it later? */
+	rc = cxl_context_init(ctx, afu, false);
+	if (rc)
+		goto err_ctx;
+
+	return ctx;
+
+err_ctx:
+	kfree(ctx);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_GPL(cxl_dev_context_init);
+
+struct cxl_context *cxl_get_context(struct pci_dev *dev)
+{
+	return dev->dev.archdata.cxl_ctx;
+}
+EXPORT_SYMBOL_GPL(cxl_get_context);
+
+int cxl_release_context(struct cxl_context *ctx)
+{
+	if (ctx->status >= STARTED)
+		return -EBUSY;
+
+	cxl_context_free(ctx);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_release_context);
+
+static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
+{
+	__u16 range;
+	int r;
+
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		range = ctx->irqs.range[r];
+		if (num < range) {
+			return ctx->irqs.offset[r] + num;
+		}
+		num -= range;
+	}
+	return 0;
+}
+
+
+int cxl_set_priv(struct cxl_context *ctx, void *priv)
+{
+	if (!ctx)
+		return -EINVAL;
+
+	ctx->priv = priv;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_set_priv);
+
+void *cxl_get_priv(struct cxl_context *ctx)
+{
+	if (!ctx)
+		return ERR_PTR(-EINVAL);
+
+	return ctx->priv;
+}
+EXPORT_SYMBOL_GPL(cxl_get_priv);
+
+int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
+{
+	int res;
+	irq_hw_number_t hwirq;
+
+	if (num == 0)
+		num = ctx->afu->pp_irqs;
+	res = afu_allocate_irqs(ctx, num);
+	if (res)
+		return res;
+
+	if (!cpu_has_feature(CPU_FTR_HVMODE)) {
+		/* In a guest, the PSL interrupt is not multiplexed. It was
+		 * allocated above, and we need to set its handler
+		 */
+		hwirq = cxl_find_afu_irq(ctx, 0);
+		if (hwirq)
+			cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
+	}
+
+	if (ctx->status == STARTED) {
+		if (cxl_ops->update_ivtes)
+			cxl_ops->update_ivtes(ctx);
+		else WARN(1, "BUG: cxl_allocate_afu_irqs must be called prior to starting the context on this platform\n");
+	}
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
+
+void cxl_free_afu_irqs(struct cxl_context *ctx)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+
+	if (!cpu_has_feature(CPU_FTR_HVMODE)) {
+		hwirq = cxl_find_afu_irq(ctx, 0);
+		if (hwirq) {
+			virq = irq_find_mapping(NULL, hwirq);
+			if (virq)
+				cxl_unmap_irq(virq, ctx);
+		}
+	}
+	afu_irq_name_free(ctx);
+	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+}
+EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
+
+int cxl_map_afu_irq(struct cxl_context *ctx, int num,
+		    irq_handler_t handler, void *cookie, char *name)
+{
+	irq_hw_number_t hwirq;
+
+	/*
+	 * Find interrupt we are to register.
+	 */
+	hwirq = cxl_find_afu_irq(ctx, num);
+	if (!hwirq)
+		return -ENOENT;
+
+	return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
+}
+EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
+
+void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+
+	hwirq = cxl_find_afu_irq(ctx, num);
+	if (!hwirq)
+		return;
+
+	virq = irq_find_mapping(NULL, hwirq);
+	if (virq)
+		cxl_unmap_irq(virq, cookie);
+}
+EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
+
+/*
+ * Start a context
+ * Code here similar to afu_ioctl_start_work().
+ */
+int cxl_start_context(struct cxl_context *ctx, u64 wed,
+		      struct task_struct *task)
+{
+	int rc = 0;
+	bool kernel = true;
+
+	pr_devel("%s: pe: %i\n", __func__, ctx->pe);
+
+	mutex_lock(&ctx->status_mutex);
+	if (ctx->status == STARTED)
+		goto out; /* already started */
+
+	/*
+	 * Increment the mapped context count for adapter. This also checks
+	 * if adapter_context_lock is taken.
+	 */
+	rc = cxl_adapter_context_get(ctx->afu->adapter);
+	if (rc)
+		goto out;
+
+	if (task) {
+		ctx->pid = get_task_pid(task, PIDTYPE_PID);
+		kernel = false;
+
+		/* acquire a reference to the task's mm */
+		ctx->mm = get_task_mm(current);
+
+		/* ensure this mm_struct can't be freed */
+		cxl_context_mm_count_get(ctx);
+
+		if (ctx->mm) {
+			/* decrement the use count from above */
+			mmput(ctx->mm);
+			/* make TLBIs for this context global */
+			mm_context_add_copro(ctx->mm);
+		}
+	}
+
+	/*
+	 * Increment driver use count. Enables global TLBIs for hash
+	 * and callbacks to handle the segment table
+	 */
+	cxl_ctx_get();
+
+	/* See the comment in afu_ioctl_start_work() */
+	smp_mb();
+
+	if ((rc = cxl_ops->attach_process(ctx, kernel, wed, 0))) {
+		put_pid(ctx->pid);
+		ctx->pid = NULL;
+		cxl_adapter_context_put(ctx->afu->adapter);
+		cxl_ctx_put();
+		if (task) {
+			cxl_context_mm_count_put(ctx);
+			if (ctx->mm)
+				mm_context_remove_copro(ctx->mm);
+		}
+		goto out;
+	}
+
+	ctx->status = STARTED;
+out:
+	mutex_unlock(&ctx->status_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(cxl_start_context);
+
+int cxl_process_element(struct cxl_context *ctx)
+{
+	return ctx->external_pe;
+}
+EXPORT_SYMBOL_GPL(cxl_process_element);
+
+/* Stop a context.  Returns 0 on success, otherwise -Errno */
+int cxl_stop_context(struct cxl_context *ctx)
+{
+	return __detach_context(ctx);
+}
+EXPORT_SYMBOL_GPL(cxl_stop_context);
+
+void cxl_set_master(struct cxl_context *ctx)
+{
+	ctx->master = true;
+}
+EXPORT_SYMBOL_GPL(cxl_set_master);
+
+/* wrappers around afu_* file ops which are EXPORTED */
+int cxl_fd_open(struct inode *inode, struct file *file)
+{
+	return afu_open(inode, file);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_open);
+int cxl_fd_release(struct inode *inode, struct file *file)
+{
+	return afu_release(inode, file);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_release);
+long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return afu_ioctl(file, cmd, arg);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
+int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
+{
+	return afu_mmap(file, vm);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_mmap);
+__poll_t cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
+{
+	return afu_poll(file, poll);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_poll);
+ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
+			loff_t *off)
+{
+	return afu_read(file, buf, count, off);
+}
+EXPORT_SYMBOL_GPL(cxl_fd_read);
+
+#define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
+
+/* Get a struct file and fd for a context and attach the ops */
+struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
+			int *fd)
+{
+	struct file *file;
+	int rc, flags, fdtmp;
+	char *name = NULL;
+
+	/* only allow one per context */
+	if (ctx->mapping)
+		return ERR_PTR(-EEXIST);
+
+	flags = O_RDWR | O_CLOEXEC;
+
+	/* This code is similar to anon_inode_getfd() */
+	rc = get_unused_fd_flags(flags);
+	if (rc < 0)
+		return ERR_PTR(rc);
+	fdtmp = rc;
+
+	/*
+	 * Patch the file ops.  Needs to be careful that this is rentrant safe.
+	 */
+	if (fops) {
+		PATCH_FOPS(open);
+		PATCH_FOPS(poll);
+		PATCH_FOPS(read);
+		PATCH_FOPS(release);
+		PATCH_FOPS(unlocked_ioctl);
+		PATCH_FOPS(compat_ioctl);
+		PATCH_FOPS(mmap);
+	} else /* use default ops */
+		fops = (struct file_operations *)&afu_fops;
+
+	name = kasprintf(GFP_KERNEL, "cxl:%d", ctx->pe);
+	file = cxl_getfile(name, fops, ctx, flags);
+	kfree(name);
+	if (IS_ERR(file))
+		goto err_fd;
+
+	cxl_context_set_mapping(ctx, file->f_mapping);
+	*fd = fdtmp;
+	return file;
+
+err_fd:
+	put_unused_fd(fdtmp);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(cxl_get_fd);
+
+struct cxl_context *cxl_fops_get_context(struct file *file)
+{
+	return file->private_data;
+}
+EXPORT_SYMBOL_GPL(cxl_fops_get_context);
+
+void cxl_set_driver_ops(struct cxl_context *ctx,
+			struct cxl_afu_driver_ops *ops)
+{
+	WARN_ON(!ops->fetch_event || !ops->event_delivered);
+	atomic_set(&ctx->afu_driver_events, 0);
+	ctx->afu_driver_ops = ops;
+}
+EXPORT_SYMBOL_GPL(cxl_set_driver_ops);
+
+void cxl_context_events_pending(struct cxl_context *ctx,
+				unsigned int new_events)
+{
+	atomic_add(new_events, &ctx->afu_driver_events);
+	wake_up_all(&ctx->wq);
+}
+EXPORT_SYMBOL_GPL(cxl_context_events_pending);
+
+int cxl_start_work(struct cxl_context *ctx,
+		   struct cxl_ioctl_start_work *work)
+{
+	int rc;
+
+	/* code taken from afu_ioctl_start_work */
+	if (!(work->flags & CXL_START_WORK_NUM_IRQS))
+		work->num_interrupts = ctx->afu->pp_irqs;
+	else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
+		 (work->num_interrupts > ctx->afu->irqs_max)) {
+		return -EINVAL;
+	}
+
+	rc = afu_register_irqs(ctx, work->num_interrupts);
+	if (rc)
+		return rc;
+
+	rc = cxl_start_context(ctx, work->work_element_descriptor, current);
+	if (rc < 0) {
+		afu_release_irqs(ctx, ctx);
+		return rc;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cxl_start_work);
+
+void __iomem *cxl_psa_map(struct cxl_context *ctx)
+{
+	if (ctx->status != STARTED)
+		return NULL;
+
+	pr_devel("%s: psn_phys%llx size:%llx\n",
+		__func__, ctx->psn_phys, ctx->psn_size);
+	return ioremap(ctx->psn_phys, ctx->psn_size);
+}
+EXPORT_SYMBOL_GPL(cxl_psa_map);
+
+void cxl_psa_unmap(void __iomem *addr)
+{
+	iounmap(addr);
+}
+EXPORT_SYMBOL_GPL(cxl_psa_unmap);
+
+int cxl_afu_reset(struct cxl_context *ctx)
+{
+	struct cxl_afu *afu = ctx->afu;
+	int rc;
+
+	rc = cxl_ops->afu_reset(afu);
+	if (rc)
+		return rc;
+
+	return cxl_ops->afu_check_and_enable(afu);
+}
+EXPORT_SYMBOL_GPL(cxl_afu_reset);
+
+void cxl_perst_reloads_same_image(struct cxl_afu *afu,
+				  bool perst_reloads_same_image)
+{
+	afu->adapter->perst_same_image = perst_reloads_same_image;
+}
+EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
+
+ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
+{
+	struct cxl_afu *afu = cxl_pci_to_afu(dev);
+	if (IS_ERR(afu))
+		return -ENODEV;
+
+	return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
+}
+EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);